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United States Patent |
5,631,884
|
Chun
|
May 20, 1997
|
Compact-disc changer using the same optical pickup device used for
playing disc for sensing roulette position
Abstract
A roulette-type disc changer includes a tray, a roulette rotatably mounted
on the tray, on the upper surface of which a plurality of discs are
loaded, and a pickup portion installed below the tray and having a deck on
which an optical pickup for emitting a laser beam moves, for reproducing
information from the discs, wherein a plurality of throughhole groups are
formed in a predetermined pattern along a circumference of the roulette, a
light throughhole is formed in the tray at a position corresponding to
that of the throughholes of the roulette, the deck of the pickup portion
is extended such that the optical pickup can sufficiently move to the
position of the light throughhole, and a reflecting device is installed
such that the laser beam emitted from the optical pickup can pass through
the light throughhole and the throughholes of the roulette and be
reflected from the reflection means.
Inventors:
|
Chun; Kyu-sam (Kyungki-do, KR)
|
Assignee:
|
Samsung Electronics Co., Ltd. (Kyungki-do, KR)
|
Appl. No.:
|
388768 |
Filed:
|
February 15, 1995 |
Foreign Application Priority Data
Current U.S. Class: |
369/30.97; 369/30.33; 720/606 |
Intern'l Class: |
G11B 017/22 |
Field of Search: |
369/37,30,75.1,75.2,54,58,36
360/98.04,98.06
|
References Cited
U.S. Patent Documents
5193079 | Mar., 1993 | Ko et al. | 369/37.
|
5293362 | Mar., 1994 | Sakurai et al. | 369/37.
|
Primary Examiner: Levy; Stuart S.
Assistant Examiner: Watkins; Kevin M.
Attorney, Agent or Firm: Limberg; Allen LeRoy
Claims
What is claimed is:
1. A roulette-type disc changer comprising:
a tray;
a roulette rotatably mounted on said tray, said roulette having an upper
surface distal from said tray for loading a plurality of discs thereon,
having a lower surface opposite its said upper surface and proximate to
said tray, and having a rim at a circumference thereof;
a pickup portion installed below said tray and having a deck on which moves
an optical pickup for emitting a laser beam and sensing the laser beam
reflected back thereto as from one of said plurality of discs, for
reproducing information from the discs; and
a reflector positioned above the upper surface of said roulette, wherein a
plurality of throughhole groups each having at least one light throughhole
therein are formed in a predetermined pattern along a circular path near
the circumference of said roulette and separate from where said plurality
of disks are loaded, wherein each light throughhole in said throughhole
groups extends between the upper and lower surfaces of said roulette at a
prescribed distance from its rim, wherein an light throughhole is formed
in said tray at a position corresponding to that of the throughholes of
said roulette, wherein the deck of said pickup portion is extended such
that said optical pickup can move sufficiently close to the rim of said
roulette as to be positioned beneath the additional light throughhole in
said tray, and wherein said reflector is positioned such that the laser
beam emitted from said optical pickup can pass through the additional
light throughhole in said tray and one of the groups of throughholes of
said roulette and be reflected by said reflector back to said optical
pickup, thereby allowing a disc number or a disc stopping position or both
to be sensed by said optical pickup.
2. A roulette-type disc changer as claimed in claim 1, wherein the deck of
said pickup portion is provided with means for limiting the outermost
movement of the optical pickup.
3. A roulette-type disc changer as claimed in claim 1, further comprising a
holder chuck coupled to said tray, for supporting and fixing a disc loaded
on said roulette.
4. A roulette-type disc changer as claimed in claim 3, wherein said
reflector is attached to said holder chuck.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a roulette-type disc changer, and
particularly to a roulette-type disc changer which can sense a disc number
using a laser beam from an optical pickup, without using an extra photo
sensor.
Along with the advent of the compact disc (CD), various types of CD players
have been introduced. While some such players accommodate (as for
reproducing) a single disc, a CD player system in which a plurality of
discs can be accommodated has been developed recently, which is called a
roulette-type disc changer. One example of a conventional roulette-type
disc changer is shown in FIGS. 1 and 2, where FIG. 1 is a plan view
thereof and FIG. 2 is a cross-sectional view which is cut along line
II--II of FIG. 1.
Referring to FIGS. 1, 2 and 3, the conventional roulette-type disc changer
10 comprises a round tray 11 having a predetermined thickness and width,
and a round roulette 12 which is installed on a rotary shaft 16 located at
the center of tray 11, to rotate the roulette 12 thereon. A plurality of
L-shaped holder chucks 11a for supporting a plurality of discs 13 are
provided around the circumference of tray 11 at a predetermined interval
from each other. Fixing members 13s for preventing disc separation from
the roulette are installed in each chuck 11a, so as to be positioned over
the center of each disc 13. Photo sensors 15 are installed in a circular
pattern on the upper surface of tray 11, for sensing disc-number sensing
interrupters 14a, 14b and 14c and a roulette-stop sensing interrupter 14d
which are arranged in a corresponding circular pattern on the lower
surface of roulette 12, as shown in FIG. 3.
In the operation of the above conventional roulette-type disk changer, when
roulette 12 loaded on tray 11 rotates, the disc-number sensing
interrupters 14a, 14b and 14c and roulette-stop sensing interrupter 14d
pass above photo sensors 15 installed between tray 11 and roulette 12.
Accordingly, each interrupter intercepts the light of photo sensors 15 so
that the disc number can be sensed by the different number of light
interceptions, which is in accordance with the number of interrupters 14a,
14b or 14c. The stop position of roulette 12 is detected by roulette-stop
sensing interrupter 14d.
However, the above-described system for sensing disc number and roulette
stop position requires an additional set of photo sensors and interrupters
for each disc. Therefore, the manufacturing cost of a CD player is
increased accordingly and the interrupter formation is troublesome.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention is to
provide a roulette-type disc changer which is capable of sensing disc
number through the utilization of a laser beam emitted from an optical
pickup, without using an additional photo sensor.
To attain the above object, there is provided a roulette-type disc
according to the present invention comprising a tray; a roulette rotatably
mounted on the tray, on the upper surface of which a plurality of discs
are loaded; and a pickup portion installed below the tray and having a
deck on which an optical pickup for emitting a laser beam moves, for
reproducing information from the discs, wherein a plurality of throughhole
groups are formed in a predetermined pattern along a circumference of the
roulette, a light throughhole is formed in the tray at a position
corresponding to that of the throughholes of the roulette, the deck of the
pickup portion is extended such that the optical pickup can sufficiently
move to the position of the light throughhole, and reflection means is
installed such that the laser beam emitted from the optical pickup can
pass through the light throughhole and the throughholes of the roulette
and be reflected from the reflection means.
Also, a sensor switch for limiting the outermost movement of the optical
pickup is provided on the deck of the pickup portion.
With such structural characteristics as described above, disc number
recognition and proper roulette stopping are possible through the
utilization of the laser beam of the pickup apparatus, without having an
extra sensor for the disk number sensing and the stopping of the roulette,
respectively, as in the prior art. Thus, manufacturing costs are reduced
and labor savings can be achieved, due to the decrease in the number of
components.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a conventional roulette-type disc changer.
FIG. 2 is a cross-sectional view cut along line II--II of FIG. 1.
FIG. 3 is a view of the disc-number and roulette-stop sensing interrupters
corresponding to the photo sensors of FIG. 2.
FIG. 4 is a plan view of a a roulette of a roulette-type disc changer
according to the present invention.
FIG. 5 is a schematic cross-sectional view showing the assembled state of
the roulette, tray and chucks of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 4, a roulette-type disc changer 20 of the present
invention has throughhole sets 22a, 22b, 22c and 22d of a predetermined
spacing and interval, which are formed along the circumference of a round
roulette 22. Specifically, a plurality n of throughhole groups 22a, 22b
and 22c for sensing each disc number n are formed near the roulette's
perimeter in correspondence with a plurality n of discs 23a, 23b and 23c
arranged with the mutual interval of 360.degree./n which, for a three-disc
disc changer, is 120.degree.. Also, throughhole groups 22d for sensing the
stop position for roulette 22 are similarly formed between throughhole
groups 22a, 22b and 22c.
Referring to FIG. 5, L-shaped holder chucks 21a are coupled to the
circumferential surface of a tray 21. A fixing member 23s for preventing
disc separation from the roulette is installed in a horizontal member 21a'
of each holder chuck 21a, so as to be positioned over the center of a
disc. A reflection plate 27 is provided on the bottom surface of a
horizontal member 21a' of holder chuck 21a at a position corresponding to
one of the throughholes (22a-22d) of roulette 22. The reflection plate 27
serves to reflect the laser beam emitted from an optical pickup 28p which
is located below tray 21. A light throughhole 21h for passing the laser
beam from optical pickup 28p is provided in tray 21 at the position
corresponding to the throughholes (22a-22d) of roulette 22. A guiding rail
(not shown) is provided in the deck 28d for the horizontal movement of
optical pickup 28p on deck 28d, and a sensor switch 29 for limiting the
outermost movement of the optical pickup 28p is provided on an extended
portion of deck 28d. Here, sensor switch 29 detects when the proper
position of optical pickup 28p along the guiding rail has been reached;
that is, the position directly below reflection plate 27. In FIG. 5, a
reference symbol 28m indicates a motor for disc rotation and 28t is a turn
table on which the discs are loaded.
Now, operation of the roulette-type disc changer having the above structure
according to the present invention will be explained in detail, with
reference to FIG. 5.
Once roulette-type disc changer 20 is activated so that roulette 22
rotates, deck 28d descends vertically while optical pickup 28p of pickup
portion 28 moves to the outer circumference of deck 28d so as to be
positioned in line with the throughhole of tray 21. When optical pickup
28p reaches the proper position, sensor switch 29 sends a detection signal
to a control unit (not shown) which stops the movement of optical pickup
28p and sets the laser beam focussing lens installed therein to a neutral
position so that the emitted laser beam can be used for throughhole
detection.
In such a condition, with roulette 22 rotating, the laser beam is passed
and interrupted according to the pattern of the disc-number-sensing
throughholes 22a, 22b and 22c formed in roulette 22, creating a pulse
signal which can be decoded. Accordingly, the respective disc number is
determined.
In a similar manner, the received laser beam pulse signal can determine the
exact position for stopping the roulette. Here, the passage and
interruption of the laser beam according to the formation of the
roulette-stop-sensing throughholes 22d at predetermined locations around
roulette 22, signify proper roulette stopping positions. Once roulette 22
is stopped at an exact position, deck 28d ascends vertically and optical
pickup 28p is moved back in order to execute a normal operation for disc
playback.
As described above, the roulette-type disc changer according to the present
invention does not include an extra sensor for sensing the disc number and
the stop position of the roulette, and utilizes the laser beam of the
optical pickup to achieve the same object. Therefore, the added cost with
respect to the installation of an extra sensor is eliminated and
manufacturing cost can be reduced accordingly.
It will be understood by those skilled in the art from the foregoing
description of a preferred embodiment of the disclosed device that various
changes and modifications may be made in the invention without departing
from the spirit and scope thereof. For example, although the present
invention has been described with reference to a three-disc CD player, it
can be applied to a system accommodating any number of discs. Further,
though the drawings show a varying number of holes to determine proper
system operation, any hole pattern is possible as long as the reflected
light is received as a recognizable pulse signal corresponding to roulette
position.
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